A loxP site flanked stop and neomycin resistance gene cassette was inserted into the 5' UTR and a mutation was engineered in exon 2. The mutation changes glutamic acid codon 177 (GAA) to an alanine codon (GCG)(p.Glu177Ala). The neo and stop cassette was removed through subsequent cre-mediated recombination. PCR and cDNA sequencing confirm the expression of the mutated transcript from this allele. (J:241009)